Solved IPv6 using Hetzner's vSwitch - can't reach host with assigned address

[nbari]

Hi, I have a server with IPv4/IPv6 working fine and would like to connect it to a vSwitch that has its own IPv6 network :

VLAN id : 4000 Subnet: 2a01:4f8:fff0:6f:: /64 Gateway: 2a01:4f8:fff0:6f::1 Usable IP addresses: 2a01:4f8:fff0:6f::2 to 2a01:4f8:fff0:6f:ffff:ffff:ffff:ffff

This is what I trying to assign address: 2a01:4f8:fff0:6f::2 to the server:

cloned_interfaces="vlan0"
ipv6_network_interfaces="em0 vlan0"
ipv6_ifconfig_em0="2a01:4f8:181:12cf::1 prefixlen 64"
ipv6_ifconfig_vlan0="2a01:4f8:fff0:6f::2 prefixlen 64 vlan 4000 vlandev em0"
ipv6_defaultrouter="fe80::1%em0"

The output of ifconfig vlan0:

vlan0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
        options=403<RXCSUM,TXCSUM,LRO>
        ether 08:60:6e:45:db:64
        inet6 2a01:4f8:fff0:6f::2 prefixlen 64
        inet6 fe80::a60:6eff:fe45:db64%vlan0 prefixlen 64 scopeid 0x5
        groups: vlan
        vlan: 4000 vlanpcp: 0 parent interface: em0
        media: Ethernet autoselect (1000baseT <full-duplex>)
        status: active
        nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>

If I add the gateway "ipv6_defaultrouter=2a01:4f8:fff0:6f::1" it works but the IPv6 address in the host stops working, until I set back ipv6_defaultrouter="fe80::1%em0"

UPDATE:

I had to add its own route using FIBS:

ifconfig_em0_ipv6="inet6 2a01:4f8:181:4155::1 prefixlen 64"
ipv6_defaultrouter="fe80::1%em0"
cloned_interfaces="vlan0"
ifconfig_vlan0="inet 192.168.1.2 netmask 255.255.255.0 vlan 4000 vlandev em0 fib 1"
ifconfig_vlan0_ipv6="inet6 2a01:4f8:fff0:6f::2 prefixlen 64 fib 1"
ipv6_static_routes="v4000"
ipv6_route_v4000="default 2a01:4f8:fff0:6f::1 -fib 1"